﻿using System;
using System.Collections.Generic;
using System.Data;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;

namespace YCsharp.Service {
    /// <summary>
    /// 基于Nopoi对xls文件操作服务
    /// <href>http://www.cnblogs.com/luxiaoxun/p/3374992.html</href>
    /// <date>2017-10-02</date>
    /// <author>ychost</author>
    /// </summary>
    public class XlsService : IDisposable {
        private readonly string fileName = null; //文件名
        private IWorkbook workbook = null;
        private FileStream fs = null;
        private bool disposed;

        public XlsService(string fileName) {
            if (!File.Exists(fileName)) {
                throw new Exception("文件不存在 " + fileName);
            }
            this.fileName = fileName;
            disposed = false;
        }

        /// <summary>
        /// 将DataTable数据导入到excel中
        /// </summary>
        /// <param name="data">要导入的数据</param>
        /// <param name="isColumnWritten">DataTable的列名是否要导入</param>
        /// <param name="sheetName">要导入的excel的sheet的名称</param>
        /// <returns>导入数据行数(包含列名那一行)</returns>
        public int DataTableToExcel(DataTable data, string sheetName, bool isColumnWritten) {
            int i = 0;
            int j = 0;
            int count = 0;
            ISheet sheet = null;

            fs = new FileStream(fileName, FileMode.OpenOrCreate, FileAccess.ReadWrite);
            if (fileName.IndexOf(".xlsx") > 0) // 2007版本
                workbook = new XSSFWorkbook();
            else if (fileName.IndexOf(".xls") > 0) // 2003版本
                workbook = new HSSFWorkbook();

            try {
                if (workbook != null) {
                    sheet = workbook.CreateSheet(sheetName);
                } else {
                    return -1;
                }

                if (isColumnWritten == true) //写入DataTable的列名
                {
                    IRow row = sheet.CreateRow(0);
                    for (j = 0; j < data.Columns.Count; ++j) {
                        row.CreateCell(j).SetCellValue(data.Columns[j].ColumnName);
                    }
                    count = 1;
                } else {
                    count = 0;
                }

                for (i = 0; i < data.Rows.Count; ++i) {
                    IRow row = sheet.CreateRow(count);
                    for (j = 0; j < data.Columns.Count; ++j) {
                        row.CreateCell(j).SetCellValue(data.Rows[i][j].ToString());
                    }
                    ++count;
                }
                workbook.Write(fs); //写入到excel
                return count;
            } catch (Exception ex) {
                Console.WriteLine("Exception: " + ex.Message);
                return -1;
            }
        }

        /// <summary>
        /// 将excel中的数据导入到DataTable中
        /// </summary>
        /// <param name="sheetName">excel工作薄sheet的名称</param>
        /// <param name="isFirstRowColumn">第一行是否是DataTable的列名</param>
        /// <returns>返回的DataTable</returns>
        public DataTable ExcelToDataTable(string sheetName, bool isFirstRowColumn) {
            ISheet sheet = null;
            DataTable data = new DataTable();
            int startRow = 0;
            fs = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
            if (fileName.IndexOf(".xlsx") > 0) // 2007版本
                workbook = new XSSFWorkbook(fs);
            else if (fileName.IndexOf(".xls") > 0) // 2003版本
                workbook = new HSSFWorkbook(fs);

            if (sheetName != null) {
                sheet = workbook.GetSheet(sheetName);
                if (sheet == null) //如果没有找到指定的sheetName对应的sheet，则尝试获取第一个sheet
                {
                    sheet = workbook.GetSheetAt(0);
                }
            } else {
                sheet = workbook.GetSheetAt(0);
            }
            if (sheet != null) {
                IRow firstRow = sheet.GetRow(0);
                int cellCount = firstRow.LastCellNum; //一行最后一个cell的编号 即总的列数

                if (isFirstRowColumn) {
                    for (int i = firstRow.FirstCellNum; i < cellCount; ++i) {
                        ICell cell = firstRow.GetCell(i);
                        if (cell != null) {
                            string cellValue = cell.StringCellValue;
                            if (cellValue != null) {
                                DataColumn column = new DataColumn(cellValue);
                                data.Columns.Add(column);
                            }
                        }
                    }
                    startRow = sheet.FirstRowNum + 1;
                } else {
                    startRow = sheet.FirstRowNum;
                }

                //最后一列的标号
                int rowCount = sheet.LastRowNum;
                for (int i = startRow; i <= rowCount; ++i) {
                    IRow row = sheet.GetRow(i);
                    if (row == null) continue; //没有数据的行默认是null　　　　　　　

                    DataRow dataRow = data.NewRow();
                    for (int j = row.FirstCellNum; j < cellCount; ++j) {
                        if (row.GetCell(j) != null) //同理，没有数据的单元格都默认是null
                            dataRow[j] = row.GetCell(j).ToString();
                    }
                    data.Rows.Add(dataRow);
                }
            }

            return data;
        }

        public void Dispose() {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        protected virtual void Dispose(bool disposing) {
            if (!this.disposed) {
                if (disposing) {
                    if (fs != null)
                        fs.Close();
                }

                fs = null;
                disposed = true;
            }
        }
    }
}
